The present invention relates to an assembling method of products and an assembling apparatus of the same, and more particularly to a mixed production system for automotive vehicles capable of producing numerous types of vehicle bodies or vehicle body parts.
Conventionally known as this kind of vehicle body assembling apparatus is the one having a circulation type transportation system wherein a plurality of carriages carrying vehicle body parts clamped by jigs are circulated along a loop-shaped transportation line and welding is carried out in a condition where the parts are laid on each carriage. More specifically, the parts are welded in predesignated stations of the assembly line for temporary and power-increased (i.e. permanent) welding steps. After finishing these welding steps, the carriage carrying the parts is transported to the next station for conducting the next step. When all the steps are finished and therefore a vehicle body is completed at the final station, the completed vehicle body is taken out of its carriage and then the carriage becoming empty at this moment is returned to the first station of the assembly line via a recovery line.
However, the jigs used for clamping parts in position are generally complicated in their configuration. Therefore, such a conventional circulation type transportation system encounters with a problem of interference caused between a welding equipment and the jigs when power-increased welding is applied to the parts laid on the carriage. In fact, conducting the power-increased welding is not feasible because of this kind of interference. Furthermore, due to complicatedness of the jigs, the circulation type transportation system will require a fairly large space and equipment, accompanying increase of cost. Hence, the temporary welding step must be separated from the power-increased welding step. In other words, the conventional circulation type assembly line requires to build an additional or exclusive line of a non-circulation type dedicated to the separated temporary welding step.
Meanwhile, as the power-increased welding step requiring transportation of carriage is carried out by the circulation type transportation system, it will inevitably require a large scale equipment and high cost or a large installation space.